CIA program was meant to kill al-Qaeda operatives

Because the program was only nascent, and because Congress had already signed off on the agency's broad authorities after the Sept. 11 attacks, the officials and some Republican legislators said that the CIA was not required to brief lawmakers on specifics about the program.

But congressional Democrats were furious that the program had not been shared with the committees. The Senate and House oversight committees were created by law in the 1970s as a direct response to disclosures of CIA abuses, notably including assassination plots against Cuban leader Fidel Castro and other foreign politicians. In addition, President Gerald R. Ford in 1976 issued an executive order banning assassinations.

But the ban does not apply to the killing of enemies in a war. The Bush administration took the position that killing members of al-Qaeda is no different than shooting enemy soldiers on the battlefield. The Obama administration, which has continued to fire missiles from Predator drones on suspected al-Qaeda members in Pakistan, has taken the same view.

Kenneth Anderson, a law professor at American University who has studied targeted killings, said the United States first made the argument in 1989 that killing terrorists would not violate the assassination ban and would be a legal act of self-defense under international law.

Such killings would be premised on the condition that authorities in the country where the terrorist was located were unable or unwilling to stop the terrorist, he said.

In legal terms, Anderson said, there is no real difference between killing a terrorist with a missile or with a handgun. “In political terms, there's a real difference,” he said. “The missile feels more like regular warfare, even if it's carried out by the CIA.”